This disambiguation page lists articles associated with the title UPD. If an internal link led you here, you may wish to change the link to point directly to the intended article.
Chronic smokers often have difficulty breathing because they develop Chronic Obstructive Pulmonary Disorder, or COPD. The two diseases that fall under that category are emphys â¦ ema and chronic bronchitis.
COPD, or chronic obstructive pulmonary (PULL-mun-ary) disease, is a progressive disease that makes it hard to breathe. Progressive means the disease gets worse over time. COPD can cause coughing that produces large amounts of mucus (a slimy substance), wheezing, shortness of breath, chest tightness, and other symptoms.